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Climate change could be making our food less nutritious

posted by Jason Kottke   Sep 18, 2017

A potential link between human-driven climate change and the nutrients in our food has some scientists worried. More study is needed, but here’s what may be happening. Plants are bingeing on the increasing amount of carbon dioxide in the atmosphere, which causes them to contain fewer nutrients and more sugar. Plants with fewer nutrients result in animals with fewer nutrients…and the humans who eat both are receiving fewer nutrients from eating the same amount of food.

Loladze and a handful of other scientists have come to suspect that’s not the whole story and that the atmosphere itself may be changing the food we eat. Plants need carbon dioxide to live the same way humans need oxygen. And in the increasingly polarized debate about climate science, one thing that isn’t up for debate is that the level of CO2 in the atmosphere is rising. Before the industrial revolution, the earth’s atmosphere had about 280 parts per million of carbon dioxide. Last year, the planet crossed over the 400 parts per million threshold; scientists predict we will likely reach 550 parts per million within the next half-century-essentially twice the amount that was in the air when Americans started farming with tractors.

If you’re someone who thinks about plant growth, this seems like a good thing. It has also been useful ammunition for politicians looking for reasons to worry less about the implications of climate change. Rep. Lamar Smith, a Republican who chairs the House Committee on Science, recently argued that people shouldn’t be so worried about rising CO2 levels because it’s good for plants, and what’s good for plants is good for us.

“A higher concentration of carbon dioxide in our atmosphere would aid photosynthesis, which in turn contributes to increased plant growth,” the Texas Republican wrote. “This correlates to a greater volume of food production and better quality food.”

But as the zooplankton experiment showed, greater volume and better quality might not go hand-in-hand. In fact, they might be inversely linked. As best scientists can tell, this is what happens: Rising CO2 revs up photosynthesis, the process that helps plants transform sunlight to food. This makes plants grow, but it also leads them to pack in more carbohydrates like glucose at the expense of other nutrients that we depend on, like protein, iron and zinc.